Current evidence and clinical utility of phenobarbital for alcohol withdrawal syndrome

Background: Phenobarbital (PB) has been acknowledged among clinicians as a potential alternative to benzodiazepines (BZD) to decrease the need for hospital length of stay and complications associated with alcohol withdrawal syndrome (AWS). However, the level of evidence, including appropriate dosing, is unclear. We aim to summarize the evidence regarding PB used in AWS and provide future agendas for research. Methods: Following the PRISMA guidelines, we searched MEDLINE, EMBASE, ClinicalTrials.gov, and WHO ICTRP for all peer-reviewed articles and clinical trials using keywords including"alcohol withdrawal", "delirium tremens", "phenobarbital," and "barbiturate" from their inception to September 18, 2022. Results: We included 20 articles, nine in the emergency department (ED) and 11 in the general floors or intensive care units (ICUs). Studies performed in the ED included two RCTs, although both suffered from a considerably small sample size. Six studies done in the general floors or ICUs compared PB and BZD monotherapy, while four compared the utility of adjunct PB in addition to BZD compared with BZD monotherapy and one was a database study without specific dosing information. Overall, there was considerable heterogeneity in PB dosing, measured outcomes, and AWS severity measurement scales. Conclusion: This systematic review summarizes the current evidence related to PB use in AWS. While considerable heterogeneity exists among studies available, PB as monotherapy without BZD may be a safe and effective alternative in AWS treatment. Future prospective studies or trials should focus on the standardization of PB dosing and outcomes.